Secondary prophylaxis among Indigenous Australians

This section focuses on BPG adherence amongst Indigenous Australians who were prescribed BPG on a 28-day regimen and who received at least one dose in 2018. If a person had more than one diagnosis (for example, of ARF and of RHD), they were included in the analysis only once. Those on a different regimen or an alternative treatment (i.e. not BPG) were excluded.

There were 3,209 Aboriginal and Torres Strait Islander people eligible for inclusion in calculations about BPG delivery in 2018. They were located in Northern Territory (1,604), Queensland (966), Western Australia (528), and South Australia (111). Of these:

  • 23% (748 people) received 100% or more of their prescribed doses
  • 19% (613) received 80% to 99% of their prescribed doses
  • 32% (1,012) received 50% to 79% of their prescribed doses
  • 26% (836) received less than 50% of their prescribed doses.

The delivery of prophylaxis was similar in 2017 and 2018, despite more people being prescribed BPG. The proportion of people receiving at least 80% of their scheduled doses is used as an indicator of prophylactic delivery at a level which is likely to protect against ARF recurrences (RHD Australia 2012). Data from the NT have shown that there is very minimal benefit when adherence is lower than 40% (de Dassel et al. 2018). In 2018, 19% of Indigenous Australians received fewer than 40% of their scheduled doses.

In 2018, 42% of Indigenous Australians (1,361 people) received at least 80% of doses. The proportion of people achieving at least 80% adherence was:

  • South Australia (63%, 70 people)
  • Northern Territory (53%, 848)
  • Queensland (30%, 291)
  • Western Australia (29%, 125).

Delivery of 100% of all the prescribed doses in a year is the gold standard for all people on prophylactic treatment. If someone is on treatment for an entire year, they should have at least 13 doses delivered. In 2018, the proportion of Indigenous Australians receiving 100% of their prescribed doses for the year, was:

  • 33% (531 people) in Northern Territory
  • 36% (40) in South Australia
  • 12% in Queensland (114) and Western Australia (63). 

Sex and age

In 2018, among Indigenous Australians prescribed prophylaxis:

  • adherence was generally lower among those aged 15–44—27% receiving less than half their prescribed doses, and 42% receiving at least 80%.
  • among those aged 0–14 and 45 and over, more than half received at least 80% of prescribed doses.
  • 11 of the 16 children aged under 5, received 80% or more of their prescribed doses.
  • adherence was similar for males and females on prophylaxis.
  • around 40% of males and females received 80% or more of their prescribed dose.
  • 28% of males and 25% of females received less than 50% of their prescribed doses.

Adherence level of Indigenous Australians with ARF and/or RHD on a 28-day regime, 2018. A horizontal stacked bar graph showing the adherence levels of Indigenous Australians prescribed secondary prophylaxis for ARF/RHD in 2018, with the option to filter by state and territory, age group and sex. Around 1 in 4 (23%) Indigenous Australians with ARF and/or RHD received the recommended number of doses in 2018, with a further 19% receiving at least 80% of doses.

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References

de Dassel JL, de Klerk N, Carapetis JR & Ralph AP 2018. How many doses make a difference? An analysis of secondary prevention of rheumatic fever and rheumatic heart disease. Journal of the American Heart Association 7(24): e010223.

RHD Australia, (ARF/RHD writing group), National Heart Foundation of Australia and the Cardiac Society of Australia and New Zealand, 2012. The Australian guideline for the prevention, diagnosis and management of acute rheumatic fever and rheumatic heart disease (2nd edn). Northern Territory: RHD Australia, Menzies School of Health Research.